Various different designs of hand held inhalers for delivering powdered medicaments to a patient have been developed. In many applications, it important to be able to reliably and repeatedly delivers a particular dosage of a medicament to a user. Powdered medicaments tend to agglomerate and form aggregated particles that are too large to remain entrained in an airflow stream that travels into the lungs of a user. Aggregated particles (e.g. those larger than about 5 microns) tend to impact on the throat of a user as opposed to passing through the airways to the lungs of a user. Thus, a full dosage may not be received in the lungs of a user. Accordingly, inhalers have utilized different mechanisms to de-aggregate the medicament. These mechanisms include using a pressurized propellant to assist in disbursing the medicament, the use of impellers to produce turbulence to which the aggregated particles are exposed and the configuration of the inhaler to produce a turbulent flow of air to de-aggregate the powdered medicament.
Inhalers that do not use a pressurized propellant typically use a stream of air traveling through the inhaler to remove the medicament from a storage chamber. A problem with some of these designs is that the stream of air is directed at the storage chamber at an angle that tends to compact the medicament thereby increasing the likelihood that aggregated particles that are too large to remain entrained in an airflow stream that travels into the lungs of a user will be formed.